Just to clarify, I'm not suggesting that your hope has vitamin poisoning and that is why is pinching feathers off, just that there is no need to feed vitamins if you're feeding a good quality mixed diet. When you say the Hawk has been bateing, is that off the fist or a bow perch?. That's really if it is malting it should be left free lifted in a pen somewhere quiet until the moat is completed you shouldn't even be picking it up really. Pinching feathers off is usually caused by knocking the wing or stress. If the bird is otherwise healthy I would avoid boxing it up and taking it to the vets in the middle of the moult and unless you are taking it to a specialist avian vet you're probably just wasting your money. Although it is probably advisable to speak to a good quality avian vet. All the best Chris